In the air quality directive (2008/EC/50), the EU has set a limit value for lead (Pb) for the protection of human health: the Pb annual mean value may not exceed 0.5 milligrams per cubic metre (µg/m3) except in the immediate vicinity of specific, notified industrial sources where the Pb annual mean value may not exceed 1.0 milligram per cubic metre (µg/m3)